Influence of Grain Boundary on Activation of Slip Systems in Magnesium: Crystal Plasticity Analysis

2010 ◽  
Vol 654-656 ◽  
pp. 695-698 ◽  
Author(s):  
Tsuyoshi Mayama ◽  
Tetsuya Ohashi ◽  
Kenji Higashida
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Crystal Plasticity ◽  
Crystal Orientation ◽  
Basal Slip ◽  
Prismatic Slip ◽  
Shear Stresses ◽  
Slip Systems ◽  
Analysis Method ◽  
Pyramidal Slip

Crystal plasticity finite element analysis method considering the accumulation of geometrically necessary (GN) dislocations was applied to monotonic loading of pure magnesium bi-crystal. The deformation mechanisms considering in the present analysis method are basal slip <a>, prismatic slip <a>, 1st order pyramidal slip <a>, 2nd order pyramidal slip <a+c> and tensile twinning <a+c>. Tensile twinning is incorporated into crystal plasticity analysis assuming that twinning plane and direction of shear by twinning are equivalent to slip plane and slip direction, respectively. Critical resolved shear stresses (CRSSs) for each slip system in the literatures were used. Analysis model is designed to investigate the influence of grain boundary on the activation of slip systems. That is, one grain consisting of bi-crystal (grain A) had the crystal orientation whose Schmid factor for prismatic slip is 0.5. The crystal orientation of the other grain (grain B) was slightly deviated from that of grain A. The result of the calculation of tensile loading of the bi-crystal showed that both grains are deformed by the multiple slip of basal slip system, which resulted in the formation of GN dislocation bands.

Transmission Electron Microscopy of Shock-Deformed Sapphire

1991 ◽  
Vol 49 ◽  
pp. 966-967
Author(s):  
S.-J. Chen
Keyword(s):  
Basal Slip ◽  
Peak Pressure ◽  
Ceramic Materials ◽  
Prismatic Slip ◽  
Slip Systems ◽  
Microstructural Characteristics ◽  
Pyramidal Slip ◽  
Transmission Electron ◽  
Show Evidence ◽  
The Impact

An understanding of the micromechanisms which occur during the shock deformation of hard ceramic materials would be helpful to the development and optimization of these materials in ballistic environments. Previous studies of shock loaded alumina show evidence of plastic flow by basal slip 1/3<110> (0001), basal twinning, pyramidal slip 1/3<010>{113} and prismatic slip 1/3<101>(110), It has also been observed that the grain boundary and interphase material (e. g. glass) play an important role in determining the microstructural characteristics. In order to elucidate the response of different slip systems, as a function of the impact orientation and the magnitude of peak pressure, some experiments with single crystal alumina (sapphire) have been carried out and the preliminary results are presented here.

Crystal Plasticity Analysis of Change in Active Slip Systems of α-Phase of Ti-6Al-4V Alloy under Cyclic Loading

2016 ◽  
Vol 725 ◽  
pp. 183-188
Author(s):  
Yoshiki Kawano ◽  
Tsuyoshi Mayama ◽  
Ryouji Kondou ◽  
Tetsuya Ohashi
Keyword(s):  
Slip System ◽  
Crystal Plasticity ◽  
Basal Slip ◽  
Slip Systems ◽  
Cyclic Plastic ◽  
Loading Direction ◽  
Α Phase ◽  
Primary Slip System ◽  
Active Slip ◽  
Plastic Loading

In this paper, we investigated changes in active slip systems of α-phase of Ti-6Al-4V alloy under a cyclic plastic loading using a crystal plasticity finite element method. In the analyses, a bicrystal model was employed, and the crystallographic orientations were set so as that prismatic <a> or basal slip system was the primary slip system in each grain. The results showed that there was a mechanism where the basal slip systems could reach the stage of activation under the cyclic plastic loading even though the condition was that the prismatic <a> slips initially operate. The reason for the activity changes was due to the changes in the incompatibility between the grains by the work hardening, and the effect of the incompatibility on activities of slip systems appeared even in the perpendicular arrangements of the grains to the loading direction.

scholarly journals Ca-induced Plasticity in Magnesium Alloy: EBSD Measurements and VPSC Calculations

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 67 ◽  
Author(s):  
Umer Masood Chaudry ◽  
Kotiba Hamad ◽  
Jung-Gu Kim
Keyword(s):  
Shear Stress ◽  
Magnesium Alloy ◽  
Slip System ◽  
Basal Slip ◽  
Room Temperature ◽  
Prismatic Slip ◽  
Slip Systems ◽  
Electron Backscattered Diffraction ◽  
Self Consistent ◽  
Critical Resolved Shear Stress

In the present work, Ca-induced plasticity of AZ31 magnesium alloy was studied using electron backscattered diffraction (EBSD) measurements supported by viscoplastic self-consistent (VPSC) calculations. For this purpose, alloy samples were stretched to various strains (5%, 10%, and 15%) at room temperature and a strain rate of 10−3 s−1. The EBSD measurements showed a higher activity of non-basal slip system (prismatic slip) as compared to that of tension twins. The VPSC confirmed the EBSD results, where it was found that the critical resolved shear stress of the various slip systems and their corresponding activities changed during the stretching of the alloy samples.

scholarly journals Quantitative study of the effect of grain boundary parameters on the slip system level Hall-Petch slope for basal slip system in Mg-4Al

2020 ◽  
Vol 200 ◽  
pp. 148-161 ◽  
Author(s):  
Mohsen Taheri Andani ◽  
Aaditya Lakshmanan ◽  
Veera Sundararaghavan ◽  
John Allison ◽  
Amit Misra
Keyword(s):  
Grain Boundary ◽  
Slip System ◽  
Quantitative Study ◽  
Basal Slip ◽  
System Level

Temperature Dependence of the Yield Stress in α-Titanium Investigated with Crystal Plasticity Analysis

2018 ◽  
Vol 941 ◽  
pp. 1474-1478
Author(s):  
Yelm Okuyama ◽  
Masaki Tanaka ◽  
Tetsuya Ohashi ◽  
Tatsuya Morikawa
Keyword(s):  
Finite Element ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Crystal Plasticity ◽  
Slip Systems ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Pyramidal Slip ◽  
Active Slip ◽  
Lattice Friction

The effect of the activated slip systems on the temperature dependence of yield stress was investigated in α-Ti by using crystal plasticity finite element method. A model for finite element analysis (FEA) was constructed based on experimental results. The displacement in FEA was applied up to the nominal strain of 4% which is the same strain as the experimental one. Stress-strain curves were obtained, which corresponds to experimental data taken every 50 K between 73 K and 673 K. The used material constants which are temperature dependent were elastic constants, and lattice friction stresses. The lattice friction stresses of basal slip systems were set to be higher than that of pyramidal slip systems at 73 K. Then, the lattice friction stresses were set to be closer as the temperature increases. It was found that the activation of slip systems is strong temperature dependent, and that the yield stress depends on the number of active slip systems.

Multiscale Crystal Plasticity Simulation with Pseudo-Three-Dimensional Model on Ultrafine-Graining Based on Evolution of Dislocation Structures

2008 ◽  
Vol 584-586 ◽  
pp. 1057-1062 ◽  
Author(s):  
Yoshiteru Aoyagi ◽  
Naohiro Horibe ◽  
Kazuyuki Shizawa
Keyword(s):  
Slip System ◽  
Dislocation Structure ◽  
Crystal Plasticity ◽  
Three Dimensional ◽  
Slip Rate ◽  
Dislocation Cell ◽  
Reaction Diffusion Equations ◽  
Slip Systems ◽  
Dimensional Model ◽  
Three Dimensional Model

In this study, we develop a multiscale crystal plasticity model that represents evolution of dislocation structure on formation process of ultrafine-grained metal based both on dislocation patterning and geometrically necessary dislocation accumulation. A computation on the processes of ultrafine-graining, i.e., generation of dislocation cell and subgrain patterns, evolution of dense dislocation walls, its transition to micro-bands and lamellar dislocation structure and formation of subdivision surrounded by high angle boundaries, is performed by use of the present model. Dislocation patterning depending on activity of slip systems is reproduced introducing slip rate of each slip system into reaction-diffusion equations governing self-organization of dislocation structure and increasing immobilizing rate of dislocation with activation of the secondary slip system. In addition, we investigate the effect of active slip systems to the processes of fine-graining by using the pseudo-three-dimensional model with twelve slip systems of FCC metal.

Evaluation of Plastic Work Density, Strain Energy and Slip Multiplication Intensity at Some Typical Grain Boundary Triple Junctions

2010 ◽  
Vol 654-656 ◽  
pp. 1283-1286 ◽  
Author(s):  
Tetsuya Ohashi ◽  
Michihiro Sato ◽  
Yuhki Shimazu
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Crystal Plasticity ◽  
Strain Energy ◽  
Plastic Work ◽  
Slip Systems ◽  
Triple Junctions ◽  
Plastic Slip ◽  
Boundary Triple

Plastic slip deformations of tricrystals with simplified geometries are numerically analyzed by a FEA-based crystal plasticity code. Accumulation of geometrically necessary (GN) dislocations, distributions of the total slip, plastic work density and GN dislocations on slip systems, as well as some indices for the intensity of slip multiplication are evaluated. Results show that coexistence of GN dislocations on different slip systems is prominent at triple junctions of grain boundaries.

Tensile Deformation of Magnesium and Magnesium Alloy Single Crystals

2014 ◽  
Vol 783-786 ◽  
pp. 341-345 ◽  
Author(s):  
Shinji Ando ◽  
Atsushi Kodera ◽  
Kazuki Fukushima ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara
Keyword(s):  
Single Crystals ◽  
Basal Slip ◽  
Tensile Deformation ◽  
Pure Magnesium ◽  
Slip Systems ◽  
Pyramidal Slip ◽  
Higher Temperature ◽  
Von Mises ◽  
Zn Alloy ◽  
Active Slip

According to von-Mises criterion, five kinds of independent slip systems are required for uniform deformation, so it is necessary to activate non-basal slip systems to show good ductility. However, it has not become clear the effect of Zn or Al for non-basal slip systems yet. To investigate deformation behavior of magnesium crystal by non-basal slip and alloying effect for the non-basal slip, pure magnesium and Mg-Al-Zn single crystals were stretched in the [110] direction. While {112}<23> second order pyramidal slip was activated at room temperature in pure magnesium, {101}<23> first order pyramidal slip became active slip at higher temperature. In Mg-Al-Zn alloy single crystal, {101} twin also activated by adding aluminum. These results indicate that active non-basal slip systems and twin in magnesium strongly depend on deformation temperature and alloying elements.

Effect of Rolling Deformation to Microstructure and Properties of Mg-8.5Li-1Al-1Ce Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 924-927
Author(s):  
Wang Tao ◽  
Mi Lin Zhang ◽  
Shu Jin Zhao ◽  
Chun Mei Song ◽  
Cheng Ju
Keyword(s):  
Mechanical Properties ◽  
Basal Slip ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Slip Systems ◽  
Melting Method ◽  
Β Phase ◽  
Pyramidal Slip ◽  
Α Phase ◽  
Rolling Deformation

Mg-8.5Li-1Al-1Ce alloys were prepared with vacuum induction melting method. Uniaxial rolling deformation of alloys was obtained by two-roll milling. The effect of rolling deformation was studied on the microstructure and mechanical properties of Mg-8.5Li-1Al-1Ce. The results show that the microstructure morphologies of α-phase, β-phase and Al2Ce-phase go through different changes under different rolling percentages, and the mechanical properties are improved with increasing deformation. Besides the basal slip system, the prism and pyramidal slip systems are also activated in α(Mg) phase, with all the slip systems in β(Li) phase being uniformly activated.

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